FACT
FACT
, which computes factorials, is surprisingly not categorized as Statistical. Instead, you'll find it on the Math & Trig Functions menu. It's easy to use. Supply it with a number, and it returns the factorial. Here are the steps:
- Select a cell for
FACT
's answer. - From the Math & Trig Functions menu, select
FACT
to open its Function Arguments dialog box. - In the Function Arguments dialog box, enter the appropriate value for the argument. In the Number box, type the number whose factorial you want to compute. The answer appears in the dialog box. If you enter 5, for example, 120 appears.
- Click OK to put the answer into the selected cell.
PERMUT and PERMUTIONA
PERMUT
enables you to calculate NPr. Here's how to use it to find 26P5, the number of 5-letter sequences (no repeating letters) that you can create from the 26 letters of the alphabet. In a permutation, remember, abcde is considered different from bcdae. Follow these steps:
- Select a cell for
PERMUT
's answer. - From the Statistical Functions menu, select
PERMUT
to open its Function Arguments dialog box. - In the Function Arguments dialog box, type the appropriate values for the arguments. In the Number box, enter the N in NPr. For this example, N is 26. In the Number_chosen box, enter the r in NPr. That would be 5. With values entered for both arguments, the answer appears in the dialog box. For this example, the answer is 7893600.
- Click OK to put the answer into the selected cell.
PERMUTIONA
does the same thing, but with repetitions allowed. Its Function Arguments dialog box looks exactly like the one for PERMUT
. Its answer is equivalent to Nr. For this example, by the way, that answer is 1181376.
COMBIN and COMBINA
COMBIN
works pretty much the same way as PERMUT
. Excel categorizes COMBIN
and COMBINA
as Math & Trig functions.Here's how you use them to find 26C5, the number of ways to construct a 5-letter sequence (no repeating letters) from the 26 letters of the alphabet. In a combination, abcde is considered equivalent to bcdae.
- Select a cell for
COMBIN
- From the Math & Trig Functions menu, select
COMBIN
to open its Function Arguments dialog box. - In the Function Arguments dialog box, type the appropriate values for the arguments. In the Number box, enter the N in NCr. Once again, N is 26. In the Number_chosen box, enter the r in NCr. And again, r is 5. With values entered for both arguments, the answer appears in the dialog box. For this example, the answer is 65870.
- Click OK to put the answer into the selected cell.
COMBINA
. Its Function Arguments dialog box looks just like COMBIN
’s. For this example, its answer is equivalent to 30C25 (142506).